Paper and method for making paper

Abstract

The invention relates to a paper that is formed of a fiber-based source material and is applicable as printing paper. According to the invention, the surface of the paper is surface-treated by arranging sufficient density on the surface, such that a mixture is arranged at least on one side of the surface of the paper for forming a surface layer, which mixture comprises pigments in an amount of 75-95% by weight of the dry weight and bonding agent in an amount of 5-25% by weight of the dry weight, and the porosity of the surface layer of the paper is less than 0.07 ml/g as defined by mercury porosimeter process. Furthermore, the invention relates to a method for making paper.

1. A paper that is formed of a fibre-based source material and is applicable as printing paper, wherein the surface of the paper is surface-treated by arranging a sufficient density on the surface, such that a mixture is arranged at least on one side of the surface of the paper for forming a surface layer, wherein the mixture comprises a pigment in an amount of 75-95% by weight based on the total dry weight of the mixture and a bonding agent in an amount of 5-25% by weight based on the total dry weight of the mixture, and the porosity of the surface layer of the paper is less than 0.07 ml/g as defined by mercury porosimeter process, and wherein the paper is applicable as printing paper in HSWO printing. 
     
     
       2. The paper according to  claim 1 , wherein the porosity of the surface layer of the paper is less than 0.06 ml/g as defined by the mercury porosimeter process. 
     
     
       3. The paper according  claim 1 , wherein the pigment is selected from the group of: kaolines, talcs, carbonates, gypsum and mixtures thereof. 
     
     
       4. The paper according to  claim 1 , wherein a plate-shaped pigment is used at least partly as the pigment. 
     
     
       5. The paper according to  claim 1 , wherein the bonding agent is selected from the group of: starches, proteins, latexes, carboxy-methyl cellulose, polyvinyl alcohol, mixtures thereof and the like. 
     
     
       6. The paper according to  claim 1 , wherein the mixture comprises pigment in an amount of 82-92% by weight based on the total dry weight of the mixture. 
     
     
       7. The paper according to  claim 1 , wherein the mixture comprises the bonding agent in an amount of 8-17% by weight based on the total dry weight of the mixture. 
     
     
       8. The paper according to  claim 1 , wherein the paper is calendered. 
     
     
       9. A method for making paper, wherein paper that is applicable as printing paper is formed of a fibre-based source material, wherein paper is surface-treated such that it is coated at least on one side with a mixture comprising a pigment in an amount of 75-95% by weight based on the total dry weight of the mixture and a bonding agent in an amount of 5-25% by weight based on the total dry weight of the mixture, for arranging sufficient density on the surface of the paper and forming a surface layer in such manner that the porosity of the surface layer is less than 0.07 ml/g as defined by mercury porosimeter process, and wherein the paper is applicable as printing paper in HSWO printing. 
     
     
       10. The method according to  claim 9 , wherein sufficient density is arranged on the surface layer of the paper in such manner that the porosity of the surface layer is less than 0.06 ml/g as defined by the mercury porosimeter process. 
     
     
       11. The method according to  claim 9 , wherein the ratio of the pigment to the bonding agent is controlled. 
     
     
       12. The method according  claim 9 , wherein the paper is calendered.